Generally, the common input device of a computer system includes for example a mouse device, a keyboard device, a trackball device, and the like. Via the keyboard device, the user may directly input characters and commands into the computer system. As a consequence, most users and most manufacturers of the input devices pay much attention to the development of the keyboard devices.
Hereinafter, the configurations and the functions of a conventional keyboard device will be illustrated with reference to FIG. 1. FIG. 1 is a schematic view illustrating the outward appearance of a conventional keyboard device. As shown in FIG. 1, plural keys 10 are installed on the surface of the conventional keyboard device 1. These keys 10 are classified into some types, e.g. ordinary keys, numeric keys and function keys. When one or more keys 10 are depressed by the user's fingers, a corresponding signal is issued to the computer, and thus the computer executes a function corresponding to the depressed key or keys. For example, when the ordinary keys are depressed, corresponding English letters or symbols are inputted into the computer system. In addition, the function keys (e.g. F1˜F12) can be programmed to cause corresponding application programs to provide certain functions.
Hereinafter, the key structure of the conventional keyboard device will be illustrated with reference to FIG. 2. FIG. 2 is a schematic side view illustrating a key structure of a conventional keyboard device. As shown in FIG. 2, the key structure 2 of the conventional keyboard device comprises a base plate 20, a scissors-type connecting member 21, a keycap 22, an elastic element 23 and a membrane switch 24. The membrane switch 24 is disposed on the base plate 20. The scissors-type connecting member 21 is arranged between the base plate 20 and the keycap 22. The elastic element 23 is disposed on the membrane switch 24, and in contact with the keycap 22. The elastic element 23 is made of a rubbery material. The base plate 20 comprises a base plate fixing structure 201 and a base plate sliding hook 202. The base plate fixing structure 201 comprises a base plate fixing hook 2011 and a stopping structure 2012. The base plate fixing structure 201 is arranged at a second side 204 of the base plate 20. An entrance 2011A of the base plate fixing hook 2011 faces the second side 204 of the base plate 20. The base plate sliding hook 202 is arranged at a first side 203 of the base plate 20. An entrance 2021 of the base plate sliding hook 202 faces the first side 203 of the base plate 20. The keycap 22 comprises a keycap fixing structure 221 and a keycap sliding hook 222. The keycap fixing structure 221 is arranged at a second side 224 of the keycap 22. The keycap sliding hook 222 is arranged at a first side 223 of the keycap 22.
The scissors-type connecting member 21 comprises a first frame 211 and a second frame 212. A first end 2111 of the first frame 211 is connected with the base plate fixing structure 201. In addition, the first end 2111 of the first frame 211 is fixed between the base plate fixing hook 2011 and the stopping structure 2012. A second end 2112 of the first frame 211 is connected with the keycap sliding hook 222. In addition, the second end 2112 of the first frame 211 may be slid in the keycap sliding hook 222. A first end 2121 of the second frame 212 is connected with the keycap fixing structure 221. In addition, the first end 2121 of the second frame 212 is fixed in the keycap fixing structure 221. A second end 2122 of the second frame 212 is connected with the base plate sliding hook 202. In addition, the second end 2122 of the second frame 212 may be slid in the base plate sliding hook 202.
When the key structure 2 is depressed, the keycap 22 is moved downwardly to push against the elastic element 23, and thus the membrane switch 24 is triggered by the elastic element 23 to generate a key signal. At the same time, the second end 2112 of the first frame 211 and the second end 2122 of the second frame 212 of the scissors-type connecting member 21 are moved within the keycap sliding hook 222 and the base plate sliding hook 202, respectively. Under this circumstance, the scissors-type connecting member 21 is switched from an open-scissors state to a folded state. Whereas, when the depressing force exerted on the key structure 2 is eliminated, an elastic force provided by the elastic element 23 is exerted on the keycap 22. Due to the elastic force, the keycap 22 is moved upwardly with respect to the base plate 20, and thus the scissors-type connecting member 21 is switched from the folded state to the open-scissors state. Consequently, the keycap 22 is returned to its original position.
The configurations of the key structure 2 of the conventional keyboard device have been described above. However, some problems occur during the process of assembling the key structure 2. For example, the first end 2111 of the first frame 211 is firstly introduced into the entrance 2011A of the base plate fixing hook 2011 from the second side 204 of the base plate 20, then the scissors-type connecting member 21 is pressed down to have the first end 2111 of the first frame 211 locate between the base plate fixing hook 2011 and the stopping structure 2012, and finally the second end 2122 of the second frame 212 is introduced into the entrance 2021 of the base plate sliding hook 202 through the entrance 2021 of the base plate sliding hook 202 from the first side 203 of the base plate 20. Since the process of assembling the key structure 2 is very complicated, it is necessary to manually assemble the key structure 2. During the assembling process, since the complicated assembling tasks may fatigue the workers, the assembling efficiency is usually unsatisfied. Moreover, during the assembling process, the improper working postures of the user may damage the base plate 20 or the scissors-type connecting member 21.